| System (period) | Series | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Ordovician | Lower | Tremadocian | 485.4±1.9 | |
| Cambrian | Furongian | Stage 10 | ~489.5 | |
| Jiangshanian |  ~494
| |||
| Paibian | ~497
| |||
| Miaolingian | Guzhangian | ~500.5
| ||
| Drumian | ~504.5
| |||
| Wuliuan | ~509
| |||
| Series 2 | Stage 4 | ~514 | ||
| Stage 3 | ~521 | |||
| Terreneuvian | Stage 2 | ~529 | ||
| Fortunian | 538.8±0.2
| |||
| Ediacaran | older | |||
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] | ||||
The Miaolingian is a third series of the Cambrian system, corresponding to the Miaolingian epoch of the Cambrian period. It lasted from ~509 Ma (million years ago) to approximately 497 Ma (IUGS 2023). It started after the Stage 4 age of the Series 2 epoch and lasted until the Paibian age of the Furongian epoch. The Burgess Shale in Canada formed in this epoch. At the end of the Miaolingian, the Guzhangian–Paibian extinction began.
Definition[]
The Global Stratotype Section and Point (GSSP) of the Miaolingian series and the Wuliuan stage was ratified in 2019. The beginning of the epoch is related to the first appearance of the trilobite species Oryctocephalus indicus. The type section is located in Jianhe County, eastern Guizhou Province, China.[2]
Subdivisions[]
Miaolingian divided into three stages (from upper to lower):
- Guzhangian (~500.5 — ~497 Ma)
- Drumian (~504.5 — ~500.5 Ma)
- Wuliuan (~509 — ~504.5)
In geochronology, all stages correspond to the same ages.
Paleogeography[]
Miaolingian geography
Gondwana, the largest continent, was located in the southern hemisphere, surrounded by large islands and microcontinents. Along its northern part were parts of the future Asia, including Kazakhstan and China. Parts of the future Asia, including Kazakhstan and China, were located near its northern coasts. Baltica was also located near Gondwana. Siberia and narrow Mongolia lay further north and moved west toward Laurentia, the forerunner of North America, including Greenland.
Miaolingian life[]
Corynexochus
Peronopsis
The active evolution of life continued in the seas. Benthic graptolites, including the families Rhabdopleuridae and Dithecodendridae, became widespread during this epoch.[3] Various sponges (Rankenella) and brachiopods (Oepikites, Linnarssonia, Stilpnotreta, Obolus) are known from the Miaolingian deposits. The flowering of arthropods continued. Numerous trilobites (Kuraspoides, Kuraspis, Corynexochus, Onchonotellus) searched for food on the seabed. Their relatives, agnostids (Lejopyge, Linguagnostus, Diplagnostus, Peronopsis), were usually small animals and swam in the water column. Among the chordates, the most numerous were conodonts. Westergaardodina and Phakelodus are known from the Miaolingian of Leningrad Oblast, western Russia.
Hallucigenia fossil
The Burgess Shale, the most famous Cambrian deposit, was formed during Wuliuan and Drumian ages. Fossils of this formation include brachiopods (Paterina, Lingulella, Acrothyra, Acanthotretella), priapulid worms (Fieldia, Ottoia, Louisella, Selkirkia), trilobites (Kootenia, Olenoides, Oryctocephalites, Ehmaniella), megacheirans (Yohoia, Leanchoilia, Alalcomenaeus), radiodonts (Hurdia, Anomalocaris) and Pikaia, a primitive chordate. Such bizarre animals as Hallucigenia, Wiwaxia and Opabinia have also beeen discovered in this deposit.
References[]
- ↑ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. https://stratigraphy.org/chart#latest-version.
- ↑ "GSSP Table - Paleozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=77.
- ↑ Jörg Maletz (2023). "Benthic graptolites (Graptolithina, Pterobranchia) in the Miaolingian (Cambrian Series 3)". Palaeobiodiversity and Palaeoenvironments. 104 (2): pp. 259–274. https://link.springer.com/article/10.1007/s12549-023-00595-x